When expressing an idea that follows a previous one, "secondly it is likely that" is a phrase that can be replaced with several synonyms to enrich the language. One option is to use "in addition," which implies that another point is being added to the discussion. Another potential synonym is "furthermore," which indicates that the speaker is continuing to build on the points that have already been made. A third alternative could be "moreover," which emphasizes that the subsequent idea reinforces or complements the previous one. These different phrases can help add variety to a piece of writing or conversation and enhance its overall clarity and impact.